Next story in Health

Video: Conjoined twins

Over the years, we've brought you many stories about operations to separate conjoined twins, risky procedures that are not always successful. This case had a happy ending. Two little girls, born last summer, joined at the head, were separated last month. And doctors say they're thrilled with how their little patients are doing. What made this particular operation go so well?

Twin sisters, seven months old, were about to go under a surgeon's knife. It’s a risky surgery that could make their lives immeasurably better, or leave one or both girls damaged -- even dead.

Blanca Cabrera: “I was thinking and a lot of things came to my mind and I thought I would never see them again.”

Born in Mexico, Blanca Cabrera and Bernardo Molina met in the small farming community of Coachella in the California desert. Never married, but together for five years, they were already the parents of two healthy daughters when they learned Blanca was pregnant again.

But on an ultrasound at three months, doctors saw news both wonderful and frightening.

Blanca Cabrera: “We went and they did the ultrasound and but it seemed like something was wrong and when they finished, they wouldn't tell me anything.”

Blanca was having twins, but the babies were conjoined. They would be born connected at the head.

Despite the risks, Blanca wanted to continue the pregnancy and in July 2004, two months premature, Crystal and Cristina Molina arrived -- in one piece.

Dr. Renatta Osterdock: “I was in the delivery room. And it was probably the most amazing birth I've seen.”

Dr. Renatta Osterdock is chief of pediatric neurosurgery at Loma Linda University Children's Hospital outside Los Angeles. She and lead plastic surgeon Dr. Andrea Ray were part of the surgical team that was preparing for this separation even before the twins were born.

Conjoined twins are rare and only about two percent of all conjoined births are what's called craniopagus twins those joined at the head like Crystal and Cristina. But, even though the condition is extremely rare, it's also extremely detectable, provided the mother receives proper, early prenatal care.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

In this case, says Dr. Osterdock, use of imaging technology provided the early warning that made all the difference, giving doctors a valuable head start.

Dr. Osterdock: “We had fetal imaging. Before they were even born I could tell mom that it looks like the brains are normal.”

Tests showed the girls' skulls were fused together, but doctors said that compared to other craniopagus twins, they had one crucial advantage. Their brains weren't connected at all.

However, doctors were concerned that the blood vessels in their brains might become intertwined as the twins aged. So doing the surgery as soon as possible was key.

Still, the operationwould be difficult and complicated. So the surgical team used 3-D computer graphics, created models of the infants and conducted a run-through surgery with the entire team. All of it to prepare and rehearse for a procedure that none of these doctors had ever done before.

The medical team picked March 3 as the day of separation. To document this rare surgery, the hospital shot footage and shared it with NBC News. The operation was risky because babies can't handle massive blood loss as well as an adult, and the surgery itself could cause an infection.

But it all worked better than expected. The separation surgery was scheduled for as long as 10 hours. It took only two. Dr. Osterdock broke the news.

Dr. Osterdock: “When I told them, my voice was quivering, because I could see the fear, and I was about to cry. And mom just broke down and started crying.”

Blanca and Bernardo could hardly wait to see their baby daughters for the first time in separate beds.

Dr. Osterdock: “The look of relief and tears, and it was really made it all worthwhile.”

Josh Mankiewicz: “That's why you go to med school.”

Dr. Osterdock: “That's why I went to med school.”

Crystal and Cristina have been home a little more than a week. And it's hard to tell they just had cranial surgery. So far this looks to be the most successful separation of craniopagus twins ever. And now after all the fear and worry, a mom and dad can count their blessings.

Bernardo Molina: “It's wonderful. It's wonderful just to hug them and playing with them. I think it's just we got so lucky.”

Crystal and Cristina will need more surgery over the next few months to reshape their skulls. Their doctors are so optimistic about their long term recovery that they predict after a year or two, you'll hardly even notice that the girls had major surgery.